Three people charged with involvement in last October's shooting attack on the U.S. Embassy in the Bosnian capital, Sarajevo, pleaded not guilty to terrorism charges on May 23.

Mevlid Jasarevic, 23, and his alleged accomplices, Emrah Fojnica and Munib Ahmetspahic, are described as adherents of the strict Wahhabi branch of Islam.

Investigators say Jasarevic opened fire on the embassy with an automatic rifle, injuring a police officer, before police shot him in the leg and arrested him. Fojnica and Ahmetspahic are accused of helping him carry out the attack.

Prosecutors say the three carried out the attack to pressure NATO to pull troops out of Afghanistan.

The shooting raised concerns about the threat posed by the radicalization of Muslims in Bosnia-Herzegovina as the country continues its recovery from the Balkans conflict in the 1990s.